I'll say it again: Hikari is not the perfect girlfriend.
This isn't precisely an evident problem with the normal canon...considering most canonically strict stories are over Daisuke vs. Takeru. But there are a few clues there.
For instance: Male Character x Hikari. I swear, Hikari has been put with every single one of the boys. All of them. Taichi (her own brother), Yamato, Koushiro, Jou, Hoi Brother #1, Hoi Brother #2, Hoi Brother #3, Takeru, Ken, Daisuke, and yes, even Iori. Miyako, Sora, and Mimi don't get nearly as much attention.
This is simply because most people tend to believe that, since Hikari is kind and sweet, she would match up fine with anyone...
Hikari, firstly, is a weak person. She has a dependency complex. She can be strong morally, but...well, I'll put it this way: "The Call of Dagomon". So she wouldn't do well with another weak person. Unlike, say, Takeru, who's practically a murderer with the darkness, or Daisuke, who despite being single-minded, can focus entirely on one goal...But someone like Koushiro would also buckle under the same pressure.
(And seriously, Taichi, Yamato, Jou, and Koushiro are too old for her. And I know Ken's a little younger than Miyako, but Iori and Hikari...this is ridiculous.)
This becomes more apparent in the crossovers. My eyes are pained with OC/Hikari, Takato/Hikari, Jian/Hikari, Takuya/Hikari, Kouji/Hikari, Kouichi/Hikari, Satoshi/Hikari, Ichigo/Hikari, Sora (KH)/Hikari...basically, "Insert Male Lead Character From Media"/Hikari.
Like I said, Hikari is not a perfect girlfriend. She has defined traits, and she has a lot of responsibility that she's not sure she has. She has strange things about her still not fully explained, and so on...
Hikari is *the* most paired canon character in Digimon Adventure. I'm not joking.
Cut it out. I'm getting pissed!